Latent doping of conducting polymers
View Patent ↗Latent doping is provided wherein a conducting polymer is mixed with a dopant in solution without the doping reaction occurring unless solvent is removed. Regioregular polythiophenes are a particularly important embodiment. A composition comprising (i) at least one polymer comprising conjugation in the polymer backbone, (ii) at least one dopant for the polymer, (iii) at least one solvent for the polymer and latent dopant, wherein the polymer, the latent dopant, and the solvent are formulated so that the latent dopant does not substantially dope the polymer when formulated, but does substantially react with the polymer when the solvent is removed. Formulation of the composition can comprise adjusting the order of mixing, the amounts of the components, and the temperature. Methods of formulating the compositions and methods of using the compositions are also provided. OLED, PLED, photovoltaic, and other organic electronic devices can be fabricated.
1. A method of formulating a latent doping composition comprising:
providing at least one polymer comprising conjugation in the polymer backbone,
providing at least one dopant for the polymer,
providing at least one solvent,
formulating the polymer, the dopant, and the solvent to form the composition wherein the composition consists essentially of the polymer, the dopant, and the solvent, and wherein the dopant does not substantially dope the polymer when the composition is formulated, but does substantially react with the polymer when the solvent is removed; wherein the polymer comprises regioregular polythiophene, the dopant is an organic dopant, and the solvent is a polar solvent; wherein the amount of polymer is from about 0.01 wt. % to about 20 wt. %, wherein the amount of dopant is from about 0.01 wt. % to about 6 wt. %, and the amount of solvent is from about 80 wt. % to about 99.9 wt. %, and
further comprising the step of removing solvent to form a film of doped polymer.
2. The method according to claim 1 , wherein the amount of polymer is from about 0.01 wt. % to about 6 wt. %, wherein the amount of dopant is from about 0.01 wt. % to about 6 wt. %, and the amount of solvent is from about 94 wt. % to about 99.9 wt. %.
3. The method according to claim 1 , wherein the composition further consists essentially of at least one additional material.
4. The method according to claim 1 , wherein the polymer has a number average molecular weight of 2,000 to 25,000.
5. The method according to claim 1 , wherein the polymer has a number average molecular weight of 3,000 to 20,000.
6. The method of claim 1 , wherein the dopant does not substantially dope the polymer for at least ten minutes after formulation and storage at 25° C.
7. The method of claim 1 , wherein the dopant does not substantially dope the polymer for at least thirty days after formulation and storage at 50° C.